PURPOSE: A construction method for a curtain wall is provided to easily and safely construct the curtain wall within a short time by successively installing the curtain wall from an upper part of a building to a lower part. CONSTITUTION: A construction method for a curtain wall comprises as follows. One or more cranes are installed at a frame located in a top layer of a building. A vertical member and a horizontal member of the curtain wall including a guide rail to an upper layer except for the top layer are individually lifted by the crane and are installed on an external wall of the building by priority. A moving unit in which a moving crane is installed is installed in the guide rail of the vertical member in order to be moved. The curtain wall is fixed to the moving crane of the moving unit, and the fixed curtain wall is lifted towards the upper layer of the building. The lifted curtain wall is connected to the upper external wall of the building. The other lifted curtain wall is installed to a lower part of the curtain wall which was already connected so that the curtain wall is successively installed from the upper layer of the building to the lower layer. [Reference numerals] (AA) Step of installing cranes at a frame located in the top layer of a building; (BB) Step of lifting a vertical member and a horizontal member of the curtain wall including a guide rail to an upper layer of the building respectively and firstly installing the members on an external wall of the building; (CC) Step of combining a moving unit fixed to the cranes and including a movable crane to the guide rail of the vertical member to be moved; (DD) Step of lifting the curtain wall towards the upper layer of the building by the moving crane of the moving unit; (EE) Step of connecting the lifted curtain wall to the upper external wall of the building; (FF) Step of successively installing the curtain wall from the upper layer of the building to the lower layer
